With my faithful helper, we folded-over the leading edge of the flaperon and cleco'd into position. I spent a lot of time doing/redoing clecos to ensure no twist was induced.
Riveted all underside rivets; worked from the center-outward riveting just on the spar, then from the middle ribs to the trailing edge, then the outer ribs. No twist.
Trimmed the ABS plastic tip; marked 10mm from the edge for sighting the rivet line thru the predrilled skin holes. Trimmed the tip to ensure a tight fit. Riveted into place.
Positioned the flaperon splice plate 15mm from the trailing edge; drilled 3 holes, then updrilled to #30. Riveted in place.